Angle-closure: risk factors, diagnosis and treatment.
BACKGROUND
Primary angle-closure glaucoma (PACG) is the leading cause of blindness in East Asia. The disease can be classified into primary angle-closure suspect, primary angle closure (PAC), and PACG. Pupil-block, anterior nonpupil-block (plateau iris and peripheral iris crowding), lens related and retrolenticular mechanisms have been suggested as the four main mechanisms of angle closure.


METHODS
The risk factors for PAC are female gender, increasing age, Inuit or East Asian ethnicity, shallow anterior chamber, shorter axial length, and genetic factors.


METHODS
The diagnosis of acute PAC is mainly clinical. Diagnosis can be made with careful slit lamp examination, including intraocular pressure (IOP) measurement and gonioscopy. The diagnosis of chronic PAC and chronic PACG also require a careful history to assess risk factors, slit lamp examination including IOP and gonioscopy. Further investigations may also be required including visual fields, ultrasound biomicroscopy, and other imaging methods.


RESULTS
In acute PAC, rapid control of the IOP needs to be achieved to limit optic-nerve damage. This can be carried out medically, and/or by laser iridoplasty. Both the affected and fellow eye should undergo laser peripheral iridotomy (PI). The aim of treating chronic PAC is to eliminate the underlying pathophysiological mechanism and to reduce IOP. This can be done by carrying out laser PI, iridoplasty, medical therapy, or surgery (trabeculectomy, lens extraction, combined lens extraction with trabeculectomy and goniosynechialysis).


CONCLUSIONS
Angle-closure glaucoma is usually an aggressive, visually destructive disease. By assessing the risk factors and diagnosing the mechanism involved in a patient's condition, the management of that patient can be tailored appropriately.
Amerasinghe
Nishani
N
Singapore National Eye Centre, 11 Third Hospital Avenue, Singapore, Singapore.
Aung
Tin
T
D000367:Age Factors; D002257:Carbonic Anhydrase Inhibitors / Q000627:therapeutic use; D005006:Ethnicity; D005260:Female; D015812:Glaucoma, Angle-Closure / Q000175:diagnosis* / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D006068:Gonioscopy; D006801:Humans; D007498:Iris / Q000601:surgery; D012307:Risk Factors; D012737:Sex Factors
D002257:Carbonic Anhydrase Inhibitors